1. Field of the Invention
The invention relates generally to salts of mono- and dialkyl esters of sulfonated dicarboxylic acids, and more particularly to compounds and compositions including salts of mono- and dialkyl esters of sulfonated dicarboxylic acids, wherein the dicarboxylic acids contain 4 to 8 carbon atoms and the alkyl groups are derived from 2-propylheptanol, and to the use of the salts.
2. Background Information
Salts of mono- and dialkyl esters of sulfonated dicarboxylic acids have been known for some time. They are also known as mono- and disulfosuccinates, respectively, and are used as surfactants inter alia in emulsion polymerization, as wetting agents for paints, for coating paper and paperboard and for pharmaceutical purposes (cf. for example the synoptic article by Breuer, W. and Höfer, R. in Tenside, Surfactants, Detergents, 2003, 40 (4), 208-214).
By virtue of its favorable properties, including for example the low dynamic surface tension of aqueous solutions, the sodium salt of di-2-ethylhexyl sulfosuccinate in particular is widely used. However, for production-related reasons and in consequence of ester cleavage reactions, the corresponding formulations contain free, i.e., unbound, 2-ethyl hexanol. In view of its unpleasant odor and taste, this free 2-ethylhexanol is a disadvantage for many applications, particularly in the food industry. In addition, both 2-ethylhexyl alcohol and the sodium salt of di-2-ethylhexyl sulfosuccinate are classified as water hazards (Water Hazard Class 2).